KR20020047882A - mixture discharge gas in plasma display panel - Google Patents

Abstract

PURPOSE: A mixed discharge gas of a plasma display panel is provided to enhance efficiency and lengthen a lifetime by controlling a composition ratio of a mixed discharge gas. CONSTITUTION: A mixed discharge gas is formed by He, Ne, or a mixed gas of He and Ne. In addition, Xe is added to the mixed discharge gas. In the mixed discharge gas, Xe content is 3 to 20 percent of the discharge gas. A pressure of the mixed discharge gas is 400 to 700 torr. The efficiency of the mixed discharge gas is improved when the Xe content is increased. However, breakdown voltage is increased since the collision is increased between gases. A lifetime of plasma display panel is lengthened when the Xe content and the pressure of the mixed discharge gas are increased.

Description

Mixture discharge gas in plasma display panel

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma display panel (PDP), and more particularly, to a composition ratio of a discharge gas for a PDP capable of achieving high efficiency and long life.

Plasma display device (PDP) is a large flat panel display device of 40 "or larger and is considered as a next-generation high-definition wall-mounted TV and a large display device for multimedia combining the functions of a TV and a PC. Recently, research and development on this is being actively conducted.

However, there are still many technical challenges to be solved for the next generation PDP development.

The challenges are: large-scale panel manufacturing technology, high-definition panel manufacturing technology, improved brightness, improved contrast ratio, reduced power consumption through improved efficiency, lower prices, and improved video quality.

Among them, the improvement of efficiency, that is, the development of PDP that can produce high brightness even at low power is a very important problem. This is because the cell structure, the type and mixing ratio of discharge gas, the optimization of driving pulse, the cathode material or the phosphor through proper understanding of discharge phenomenon It can be obtained through improving the physical properties of the material, such as.

Such a PDP discharge cell structure is a representative structure of a coplanar electrode type ACPDP cell of Fujitsu, Japan, which is disclosed in US Patent 5,661,500.

The Fujitsu type three-electrode surface discharge ACPDP cell structure is illustrated in FIG. 1.

As shown in FIG. 1, the three-electrode surface discharge ACPDP cell structure can be roughly divided into an upper plate 20 and a lower plate 40, and the upper plate 20 is configured as follows.

On the surface of the front glass 21 are two side by side sustain electrodes 22 and 23, which are transparent electrodes 22-1 and 23-1 and a bus above them. It consists of bus electrodes 22-2 and 23-2.

A dielectric layer 31 is formed on the sustain electrodes 22 and 23, and a protective layer 32 is formed thereon. Since the main material of this protective film 32 is MgO, it is also called MgO film.

In the lower plate 40, an address electrode 42 is formed on a lower glass 41 in a direction perpendicular to the sustain electrodes 22 and 23, and a dielectric layer 43 is formed thereon. A barrier rib 45 is formed thereon in a direction parallel to the signal electrode 42, and a phosphor 44 is deposited thereon.

The structure configured as described above is called a three-electrode coplanar electrode type surface discharge structure, or simply a three-electrode surface discharge structure.

Looking at the operation of the three-electrode surface discharge structure according to the prior art configured as described above are as follows.

In order to light a particular cell, one of the sustain electrodes 22 and 23 of the cell is selected as a scan electrode, and a signal discharge interacting with the signal electrode 42 in the cell. causes a discharge).

At this time, charges generated by the signal discharge are accumulated on the surface of the protective layer 32 to form wall charges.

After that, when sustaining discharge is applied between the two sustain electrodes 22 and 23, the cell on which the wall charge is formed is turned on, and the cell not on the other is not lit.

When the sustain discharge is applied, the electrical polarities of the two sustain electrodes 22 and 23 are continuously changed, which is why the ACPDP operation method is used.

Looking at the principle of the light on the cell in detail as follows.

First, the upper and lower plates 20 and 40 of FIG. 1 are sealed and a chemically stable inert gas (usually containing a small amount of Xe) is injected therebetween. At this time, the inert gas contains a small amount of Xe.

Subsequently, when sufficient voltage is applied between the electrodes of the discharge cell, the gas is ionized by the collision between the electrons and the inert gas. When the gas ions reach the cathode, secondary electrons are emitted from the protective film (MgO) 32.

As these secondary electrons move toward the anode, they collide with the gas present in the cell, where a large amount of free electrons are generated and discharge begins.

At this time, the generated free electrons excite Xe atoms, and a VUV (Vacuum ultraviolet ray) is emitted from these excitation species, which in turn excite the phosphor 44 to obtain visible light.

This process of obtaining visible light from the PDP is very complicated, which is why the visible light emitting process is less commercialized than the simple CRT.

However, even after such a complicated light emission process, PDP can be commercialized because it can realize high efficiency, and the most essential thing for the high efficiency is mixed gas development.

In the PDP panel, the lifetime of the panel is determined by the etching of the protective film by the gas ions or the deterioration of the phosphor, which greatly depends on the protective film or the sputtering resistance of the phosphor, but also greatly depends on the type of discharge gas used.

And when the PDP is commercialized, the required lifetime of the PDP is 10,000 hours or more, and the lifetime of the PDP is close to 10,000 hours, but this may be improved depending on the type of gas mixture, composition ratio, and pressure.

Therefore, the present invention has been made to solve the above problems, the object of the present invention is to implement a high-efficiency, long-life color ACPDP using a mixed discharge gas.

1 is a view showing the structure of a Fujitsu type three-electrode surface discharge ACPDP cell according to the prior art;

Figure 2 is a graph showing the change in efficiency and breakdown voltage according to the X content of Xe according to the present invention

Figure 3 is a graph showing the change in efficiency and breakdown voltage according to the gas pressure according to the present invention

Figure 4 is a graph showing the comparison of the efficiency of the mixed gas of similar driving voltage according to the present invention

5 is a diagram illustrating a comparison of PDP lifespan according to various driving conditions according to the present invention.

Explanation of symbols for main parts of the drawings

20: top plate 21: top plate

22: sustain electrode (X) 22-1, 23-1: transparent electrode for sustain electrode

22-2, 23-2: bus electrode for sustain electrode

23 sustain electrode Y 31 top dielectric layer

32: protective film 40: bottom plate

41 lower substrate 42 signal electrode

43: lower dielectric layer 44: phosphor

45: bulkhead

Characteristic of the mixed discharge gas of the PDP according to the present invention for achieving the above object is a mixed discharge gas of the PDP containing Xe, He, Ne or Xe content of 3 to 20% of the mixed gas of the two Included are its features.

At this time, the pressure of the mixed gas is 400 to 700 torr but there are other characteristics.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of the mixed discharge gas of the PDP according to the present invention will be described with reference to the accompanying drawings.

2 is a graph showing simulation results showing changes in efficiency and breakdown voltage according to the% content of Xe according to the present invention.

2, the efficiency increases as the% content of Xe increases in the Ne / Xe mixed gas, but at the same time, when the content of Xe increases, collisions between gases become severe, making it difficult for electrons to have high energy enough to ionize gas atoms. This causes a problem of increasing the breakdown voltage.

One of the most effective research directions is to find a protective film with high secondary electron emission coefficient for Xe ions.

Therefore, the driving voltage can be lowered in various ways and a high efficiency discharge can be obtained by using a mixed discharge gas in which Xe is mixed as much as possible (3% to 20%) at the given driving voltage.

3 is a graph showing the results of simulating the change in efficiency and breakdown voltage according to the gas pressure according to the present invention.

3, the efficiency increases with increasing gas pressure, and under high pressure, the collision between gases increases, and thus the breakdown voltage also increases.

Therefore, the increase in gas pressure shows an increase in efficiency similarly to the increase in content of Xe, but at the same time, a problem arises in that the breakdown voltage is increased.

Therefore, the increase in gas pressure also lowers the breakdown voltage and driving voltage as much as possible in various ways, and a high efficiency discharge can be obtained by using a mixed discharge gas with the highest gas pressure (400-700 torr) under the given low driving voltage.

Figure 4 is a graph showing the comparison of the efficiency of the three mixed gas with similar driving voltage according to the present invention.

4, it can be seen that increasing the% of Xe by 2% is more effective in increasing efficiency than reducing the gas pressure by 50 Torr rather than reducing the% of Xe by 2% and increasing the gas pressure by 50 Torr.

In other words, the higher the gas pressure and the higher the% content of Xe, the higher the efficiency and the higher the driving voltage. In view of the same increase in the driving voltage, increasing the% content of Xe increases the gas pressure. It is more effective in increasing efficiency than that.

Based on the above description, Fig. 5 shows the result of calculating the lifespan change of the PDP according to various driving conditions according to the present invention.

Increasing the gas pressure, as calculated in FIG. 5, increases the collision between gases, making it difficult for electrons to have energy high enough to ionize gas atoms, and also reduce the energy of ions, thereby decreasing the rate of etching the protective film. This can extend the life of the panel.

In addition, as the% content of Xe increases, the number of Xe ions increases more rapidly than the number of Ne ions in the PDP discharge cell, which is advantageous for the life of the protective film because the sputtering yield of Xe ions is much smaller than that of Ne ions.

Therefore, the higher the gas pressure and the higher the% content of Xe, the longer the life of the panel.

However, if the% content of Xe is excessively high, that is, if the% content of Xe is increased to 20% or more, charge transfer between Xe ions and Xe atoms becomes easy while charge transfer between Ne ions and Ne atoms. ) Becomes difficult. This increases the energy of Ne ions reaching the protective film and increases the sputtering yield of the ions, thereby shortening the protective film life.

Therefore, as a condition of optimization considering efficiency and life, the% content of Xe should contain 3-20%, and the pressure of gas should be maintained at 400-700 torr.

The mixed discharge gas of the PDP according to the present invention as described above has the following effects,

First, by using a chemically stable inert gas it is possible to maintain a long life of the panel.

Second, high brightness can be obtained by using a gas capable of producing a strong VUV.

Third, color purity can be improved by using a gas that emits less visible light.

Fourth, the light conversion rate from VUV to visible light can be increased by using a gas that emits a long wavelength VUV.

Fifth, by using a mixed gas that can maintain the discharge at a low voltage, it is possible to increase the efficiency by reducing the power consumption.

Sixth, the problems of high efficiency and long life caused by color ACPDP can be greatly improved by optimizing the conditions such as the type, composition ratio, and pressure of the mixed discharge gas.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (2)

In the mixed discharge gas of the PDP containing Xe, He, Ne or the mixed discharge gas of the plasma display device, characterized in that the content of Xe contained in 3 ~ 20% of the two mixed gases. The method of claim 1, The mixed gas of the plasma display device, the pressure of the mixed gas is 400 to 700 torr.